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SAP. (a sticky subject?)

October 6, 2011

From time to time we get asked about SAP, you know, the gel-like stuff inside diapers. Does it work? Is it safe? Can I play with it? Answers: yes. yes. and umm, okay, sure…

The tougher questions we hear about SAP are regarding its safety. There’s a lot of misinformation and skepticism out there because (high fives) PARENTS ARE AWESOMELY WELL-INFORMED! Or at least we all try our very best to be. Though a Google search will turn up a variety of interesting feedback, there’s not much that will actually point you to the hard science behind this fascinating little ingredient. So we have that conveniently collected, inspected, and collated (were this on paper) the hard science facts for your parental due diligence. Here it is:

SAP (sodium polyacrylate) has been rigorously tested both in the US and abroad. The general conclusions are that it is completely safe and non-toxic.MBDC is the leading US based design chemistry firm. MBDC has assessed SAP as GREEN, which is the safest assessment a chemical or material can receive.

It’s on the PAFA list – these are things the FDA has approved for adding to food.

SAP has an oral LD50 of40g/kg. It means that a 10 lb baby would have to eat about 200 grams to be at risk (about 50 gRefills). Also to put this number in perspective, an Oral LD50 of 10g/kg is considered “harmless” by EPA standards. Typical table sugar is somewhere between 10-20g/kg so SAP is less toxic via ingestion than table sugar.

The Danish EPA determined that “No serious adverse effects were observed by oral, dermal or pulmonal administration”. This means it’s safe to be used against skin. Additionally they determined that this substance was not toxic to aquatic organisms.

CCRIS (Chemical Carcinogenesis Research Information System) determined that this substance is not mutagenic in bacterial tests (Ames) and in Eukaryotic tests (tests with mammalian cells).

BIBRA Information Services Ltd (a UK organization) employs a team of toxicologists to review substances and they have determined that oral administration of sodium polyacrylate to pregnant rats did not produce foetotoxicity or teratogenicity (birth defects) at doses up to maternal toxicity levels.

What you may read about in blogs and such is the reference to TSS (toxic shock syndrome), when SAP was pulled from tampons in the early 80’s. There was concern that the two were linked. But the truth is, it wasn’t. Just a couple of years ago Newsweek reported an uptick in TSS (2 decades after SAPs removal from tampons). The cause of TSS was not the absorbency that the FDA assumed in the 80’s, but the over-extended use of a single tampon over a prolonged period, allowing for bacteria to build up.

A while back Mothering magazine included an article citing many of the concerns about SAP that are out there. The following issue they printed a letter to the editor (Jan/Feb 2007) that debated these concerns on scientific grounds. The letter to the editor author (Susan Manning, PhD) followed up on a study that Mothering cited — she went directly to the co-author of a study that “mice exposed to disposable diapers suffered from respiratory problems”. She asked the co-author (Mr. Anderson of Anderson Laboratories) about this and he said he was misquoted, the respiratory problems they found in mice were due to the added perfumes in most disposables. She asked if there were problems with SAP and “he replied that he knew of none”.

So why is there SAP in diapers? And in our disposable inserts? Because it works amazingly well. The fact remains that there does not yet exist an ingredient with the same absorbent qualities. Its sole function is to capture moisture, and then slowly release it (an action that occurs after your baby is done using it, thankfully). To get close to the same amount of absorbent capacity we would have to use a ludicrous amount of fluff pulp (the other ingredient in our disposable inserts), which isn’t sustainable from an environmental standpoint, and isn’t comfortable for baby.

A nice thing about SAP is that it keeps working even after disposal. When the wet inserts are composted the SAP will hold and then slowly release moisture in your garden. In fact, SAP is marketed in nurseries as “water holding crystals”. When flushed, the SAP is complimentary to the waste water process, by helping separate the liquids from the solids and creating Biosolids (fertilizer for land application).

We understand that parents want to feel good about what goes against their baby’s skin. We completely agree. We’re all parents here! (Well, 17 of the 18 anyway). No way would we use a product that we didn’t feel 100% certain about. A couple of highlights that really sealed the deal for us: SAP is less toxic than table sugar, it is inert in nature, it is a common ingredient in high-end fertilizers (and is therefore sitting in the soil right alongside our potatoes and strawberries!), it has received a green certification (a feat not so easily accomplished!), and that the scientific studies all point to the conclusion that SAP is a completely safe ingredient. We wouldn’t settle for anything less.